1. Field of the Invention
The present invention relates generally to cable couplers for the connection of armored cables having armor layers and methods of holding the armor layers and, more particularly, to a cable coupler for the connection of an armored cable having an armor layer which is constructed such that the armor layer, which is formed by weaving pieces of material, such as metal, plastic, fabric, etc., or is made of tape, strips or strands, which are not woven, so as to reinforce the cable, can be reliably grounded to and held by the cable coupler, and such that several kinds of armor layers having various thicknesses can be grounded to and held by the cable coupler merely by changing the positions of a fastening ring and a support ring, thus enhancing the usefulness of the cable coupler, and a method of holding the armor layer using the coupler.
2. Description of the Related Art
Generally, as shown in FIG. 4, in a conventional cable coupler for armored cables, a fastening ring 3 has an angle of inclination such that only one kind of armor layer 1 having a corresponding thickness can be held by the cable coupler. Hence, in the case where a user needs to use several kinds of cables having armor layers of various thicknesses, the user must prepare many kinds of cable couplers corresponding to the thicknesses of the armor layers of the cables, thus increasing the economic burden on the user. Furthermore, manufacturers must also manufacture all kinds of cable couplers corresponding to various thicknesses of the armor layers of the cables, and this is economically irrational. Thus, there are few manufacturers who manufacture all kinds of cable couplers, because this incurs high production costs. As a result, there is a problem in that users may have to select and use unsuitable cable couplers.
In an effort to overcome the problems experienced with the above-mentioned conventional technique, as shown in FIGS. 5A and 5B, a cable coupler having an improved structure was proposed. In this technique, the cable coupler includes a fastening ring 5, the inner surface of which is brought into contact with an inclined surface 4a of an outer surface of a sleeve 4 and includes inclined surfaces 5a and 5b, which are inclined at different angles. As shown in FIGS. 5A and 5B, this cable coupler is constructed such that several kinds of armor layers 1 having different thicknesses can be held between the sleeve 4 and the fastening ring 5 by changing the orientation of the fastening ring 5, which is provided with the inclined surfaces 5a and 5b having different angles of inclination. However, in the conventional cable coupler shown in FIGS. 5A and 5B, in the case where the armor layer 1 to be held by the cable coupler is made of relatively thick wires having a diameter of 1 mm or more, because the width of the fastening ring 5 is relatively large, when the fastening ring 5 is inserted between a cylindrical housing 8 and a sleeve 4 and the cylindrical housing 8 is tightened to an adaptor 7, a large force is required to bend the armor layer 1 made of thick wires. Therefore, there is a disadvantage in that it is difficult to tighten the cylindrical housing 8 to the adaptor 7 using only the hands, and thus a tool such as a spanner is required. Moreover, even when such a tool is used, a large force is required, with the result that labor efficiency is markedly reduced. Furthermore, because the width of the fastening ring 5 is large and large force is required when tightening the cylindrical housing 8 to the adaptor 7 or loosening it therefrom, it is very difficult to confirm whether the armor layer 1 is correctly and reliably connected to the sleeve 4.